The Republican effort to replace Obamacare got a much-needed boost Wednesday when two congressmen agreed after meeting with President Donald Trump to drop their opposition to the GOP bill and vote for it.

Reps. Billy Long and Fred Upton said they are now "yes" votes on the bill because of the addition of an amendment that will add $8 billion in federal funding to reduce insurance costs for people with pre-existing health conditions.

Long, R-Mo., and Upton, R-Mich., earlier this week said they would oppose the bill because it could harm people with pre-existing conditions by allowing states to win waivers for insurers who wanted to charge such customers higher premiums under certain conditions.

Republican leaders have said they won't call for a vote until they know it will pass.

Leslie Dach, director of the Obamacare-supporting group Protect Our Care Campaign, said the amendment that swayed Upton and Long is "nothing more than a bailout for House Republicans as their latest desperate attempts to repeal health care continue to face strong public opposition."

"This possible amendment doesn't change the underlying truth of the Republican health-care repeal — it guts protections for people with pre-existing conditions. The GOP plan requires people with pre-existing conditions to get special insurance that costs more and covers less," Dach said.

"Now they think they can fix it by handing $62 per person to the estimated 129 million people with pre-existing conditions in this country? It isn't a solution, it's an insult," he said. "The health-care repeal will cut coverage from millions, raise your premiums and eliminate your protections, and nothing they are proposing changes those facts."

A Politico/Morning Consult poll released Wednesday found that 50 percent of Americans oppose allowing states to opt out of requiring that insurers cover pre-existing conditions. Another 38 percent support the idea of that.

And nearly 60 percent of poll respondents said that Congress should wait for the Congressional Budget Office to analyze the revised bill before voting on it. A CBO study of a past version of the bill found that it would lead to 24 million more people becoming uninsured over the next decade, and sharp premium hikes over the next two years for individual health plans.